Today, some sidelights on the history of dogs. The
University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.

A recent issue of
Discovering Archaeology magazine has two
articles on dogs. We've long supposed that the
symbiosis between human and dog developed as dogs
followed Neolithic hunters and scavenged scraps.
But animal species don't bond the way human and dog
have bonded without there being a balance of
benefits. So what was in it for the humans? The
common assumption was that animals offered
companionship in exchange for food, and that humans
accepted the gift. Although that much appears be
true, the gift of companionship runs a lot deeper
than we realized.

Archaeological evidence now shows that wolf-like
animals first evolved in the Americas. They
migrated to Europe over the Bering Strait land
bridge ten million years ago. Dogs didn't evolve
away from wolves until only 130,000 years ago. That
makes dogs about as old as the Neanderthals. We
modern humans didn't appear until 40,000 years ago,
and we've domesticated dogs for only a scant 14,000
years. That's roughly when human burials begin to
include the remains of dogs.

Biologist Wolfgang Schleidt describes evidence that
humans both profited and learned from wolves and
dogs, long before any bonding or domestication took
place. Humans following reindeer (and other) herds
would hunt the best specimens. That would've led to
weakened herds. But canine packs followed the same
herds, weeding out the weakest animals. They did
humans a service by maintaining the quality of the
herds.

More than that, canines taught cooperative hunting
to humans. Wolves and dogs are unique among animals
for the texture of their cooperation. They don't
compete within the pack; they form friendships
instead. Apes and monkeys don't do that. An ape
bonds to a mate, or to its children, but a dog has
friends beyond its kin.

So human and dog joined forces in the hunt, and
dogs helped to humanize us (or to doggify us). We
find an early stone-age farmer buried with tools
for grinding grain and with his favorite dog. A
brick from the third-millennium-BC City of Ur is
stamped with an inscription. But it has also been
marred by four dog footprints left in the once-wet
clay. A sixteenth-century crowd scene painted by
Pieter Brueghel shows a blind man with a seeing-eye
dog.

We've all been led to think that dogs are just one
more house pet. It turns out that they're much
more. They were part of our process of coming of
age. Now we find that bonding with a dog lowers our
blood pressure, cholesterol and triglycerides. We
suffer less depression. No wonder Elizabeth Barrett
wrote these lines when her dog died:

Therefore to this dog will I,
...
Render praise and favor:
With my hand upon his head,
Is my benediction said
Therefore and forever.

I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.